This Phase I research program will evaluate the feasibility of obtaining microanalytical characterization of organic species contained in biological tissue specimens. This organic microprobe feasibility evaluation will be performed using state of the art secondary ion mass spectrometry (SIMS) ion microscope and microprobe instrumentation. The optimum SIMS analytical conditions required to generate useful molecular or characteristic fragment ion intensities from selected organic species dispersed on or contained in matrices having a chemical composition similar to dehydrated soft biological tissues will be evaluated. The lateral resolution of these characteristic ions produced in the imaging SIMS analysis of these test samples will also be determined. The feasibility of employing sub-micrometer diameter ion sources in the molecular SIMS microanalysis of biological specimens will also be evaluated. The utility of a high mass range, imaging time of flight SIMS (TOFSIMS) instrumental configuration for organic microprobe analyses will also be determined. The capability of performing organic species analysis at micrometer or sub- micrometer lateral resolution would find extensive utilization in biomedical research and possibly clinical medicine. The research described in this proposal could lead to the development of innovative instrumentation or analytical methods for organic microprobe analysis.